1. Field of the Invention
The present invention relates to a technique for stereoscopic viewing.
2. Description of the Related Art
A VR (Virtual Reality) system presents a three-dimensional (3D) CG (Computer Graphic) picture created by a computer to the user to make him or her experience a virtual space as if it were a physical space.
In recent years, a technique for presenting, to the user, information which does not actually exist on the physical space by compositing a 3D CG on a picture of the physical space has been developed. Such technique is called an MR (Mixed Reality) system. This MR system draws attention as a technique that aims at the coexistence of a virtual space which could be experienced in only a situation separated from the physical space, and the physical space, and augments the virtual space.
As a representative apparatus which implements a system (VR/MR system) that allows the coexistence of the virtual and physical spaces, a head mounted display (HMD) is known. In the VR/MR system, by displaying the virtual or physical space on the HMD, the virtual space and mixed reality space can be presented to the user who wears the HMD (see Japanese Patent Laid-Open No. 2002-159019).
FIG. 1 illustrates a state in which the user wears a stereoscopic video see-through HMD 100 (to be simply referred to as an HMD 100 hereinafter). The HMD 100 has an outer appearance shape similar to spectacles or goggles, and a display device 102R for the right eye and display device 102L for the left eye, which are such as LCDs, are arranged in the HMD 100. The display device 102R for the right eye will be referred to as a right display device 102R, and the display device 102L for the left eye will be referred to as a left display device 102L hereinafter. Upon acquiring a stereoscopic video picture by video cameras equipped in the HMD 100, a stereoscopic video camera 101R for the right eye and stereoscopic video camera 101L for the left eye are arranged in the vicinity of, e.g., the viewpoint position of the user (wearer). The stereoscopic video camera 101R for the right eye will be referred to as a right camera 101R, and the stereoscopic video camera 101L for the left eye will be referred to as a left camera 101L hereinafter.
In order to implement stereoscopic viewing (to present a stereoscopic image to the user), a pair of images having disparity like images for the right and left eyes need to be generated and be displayed on the display devices for the right and left eyes. In order to generate images having disparity, the disparity between the right and left eyes, i.e., the position and orientation of the other camera viewed from one camera need to be calculated. As a method of calculating this, a method of capturing a plurality of test images by the cameras for the right and left eyes, and calculating the position and orientation relationship between the cameras from the plurality of test images is known.
Conventionally, images for the right and left eyes are generated using one image processing apparatus. However, in order to speed up image generation, the images for the right and left eyes may be generated by independent image processing apparatuses. In such arrangement, in order to calculate the positions and orientations of the cameras for the right and left eyes, the user must define, in advance, the connection relationship between the image processing apparatuses connected to these cameras. However, when the user defines a wrong connection relationship upon actually connecting the image processing apparatuses, the connected image processing apparatuses cannot correctly calculate the positions and orientations of the cameras for the right and left eyes.